Adjustable laser surgery system

ABSTRACT

Systems and methods for adjusting an angle of incidence of a laser surgery system include a laser source to produce a laser beam and an optical delivery system to output the laser beam pulses to an object at an adjustable incident angle. A first rotator assembly receives the beam from the laser source along a first beam axis. The first rotator assembly rotates around the first beam axis and the first rotator assembly outputs the beam along a second beam axis different from the first beam axis. A second rotator assembly receives the beam from the first rotator assembly along the second beam axis. The second rotator assembly rotates around the second beam axis. The second rotator assembly follows the rotation of the first rotator assembly and the first rotator assembly is independent of the rotation of the second rotator assembly.

RELATED APPLICATIONS

This application is a non-provisional application and claims the benefitunder 35 U.S.C. § 119(e) of U.S. Provisional Application Ser. No.62/115,504, filed Feb. 12, 2015, which is incorporated herein in itsentirety by reference.

FIELD OF INVENTION

This disclosure relates generally to a laser surgery system producing apulsed laser beam for inducing photodisruption at a desired angle totreat a material, such as eye tissue. Although specific reference ismade to cutting tissue for surgery, including for example, eye surgery,embodiments as described in this disclosure can be used in many ways totreat many different materials, including for example, cutting opticallytransparent materials.

BACKGROUND

Vision impairments such as myopia, hyperopia and astigmatism can becorrected using eyeglasses or contact lenses. Alternatively, they can becorrected with eye surgery. Surgeons have traditionally performed eyesurgery using manual surgical tools, such as microkeratomes and forceps.More recently, however, laser ophthalmic surgery has gained popularitywith lasers being used in a variety of ways to treat visual disorders.

A surgical laser beam is preferred over manual tools because it can befocused accurately on extremely small amounts of ocular tissue, therebyenhancing precision and reliability of the procedure, as well asimproving healing time. Indeed, studies show that more patients achievean improved level of post-operative visual acuity in the months aftersurgery with a laser system than with manual tools.

Depending on the procedure, and/or the required visual correction orindication, laser eye surgery may involve one or more types of surgicallasers, including for example, ultraviolet excimer lasers, andnear-infrared, ultra-short pulsed lasers that emit radiation in thepicosecond or femtosecond range. Non-ultraviolet, ultra-short pulsedlasers emit radiation with pulse durations as short as 10 femtosecondsand as long as 3 nanoseconds, and with a wavelength between 300 nm and3000 nm. Both ultraviolet and non-ultraviolet ultra-short pulsed lasersare used in the commonly-known LASIK (laser in-situ keratomileusis)procedure that is used to correct refractive errors.

With the LASIK procedure, surgeons typically use a non-ultraviolet,ultra-short pulsed laser to cut a superficial flap in the cornea, whichis still attached to epithelial tissue in a hinged area. The surgeonlifts the flap to expose the corneal stroma, which he or she thenphotoablates with an ultraviolet excimer laser to reshape the cornea.Reshaping the cornea helps correct refractive vision problems such asmyopia, hyperopia, and astigmatism. Cornea can also be reshaped usingother procedures such as photorefractive keratectomy (“PRK”).

Besides cutting corneal flaps, ultra-short pulsed lasers are used forother types of eye surgery, including for example, performing incisionsfor corneal implants, performing intrastromal incisions for refractivecorrection, as well as for incisions for cataract surgery, such as clearcorneal incisions that allow access to the lens capsule, capsulotomythat incises the capsular bag for access to the cataractous lens, andincisions in the lens for softening and segmenting the lens so it can beremoved from the eye, and replaced with an artificial intraocular lens.

Conventional ultra-short pulse laser systems have been used to cuttissue and to treat many patients. Many of these systems, however, mayprovide less than ideal results in at least some instances,particularly, in aligning the eye with the laser surgery system's outputbeam.

Further, conventional laser surgery systems are physically large, heavy,and stationary and as a result, employ a fixed vertical angle ofincidence of the output beam. As illustrated in FIG. 8, a conventionallaser beam 800 has a vertical angle of incidence along the Z-axis. TheXY plane is parallel to a ground surface while the Z-axis isperpendicular to the ground surface. Some of these conventional lasersystems are known to incorporate subsystems that move the output pointof the laser beam pulse horizontally and vertically while maintainingthe same fixed vertical angle of incidence. While some ultra-short pulselaser systems include a treatment arm or head to output a beam that maybe adjusted along the X-axis, Y-axis and Z-axis, other systems include afixed treatment arm. These systems provide only limited adjustability ofthe laser beam. Hence, the laser beam's angle of incidence is notadjustable in any current system. Rather, all laser surgery systemsprovide only a fixed vertical angle of incidence, where the output laserbeam is always perpendicular to the plane of the floor.

Because of these limitations, the standard procedure has been to adjustthe position of a patient's eye relative to the fixed vertical angle ofincidence of the beam. Generally, a patient bed is provided for apatient to lie horizontally such that the patient's eye may bemaneuvered to intersect perpendicularly with the laser beam. This fixedangle of incidence, however, may pose constraints on patients withabnormal body shapes and conditions, who are unable to lie flat on apatient bed. Examples of these patients include those with scoliosis orother conditions where the back is abnormally bent, and therefore,cannot lie flat. Indeed, in at least some such instances, the patient'sback and head may be tilted such that the beam is unable to intersectthe eye perpendicularly even if the eye is aligned directly beneath thebeam. In some cases, makeshift solutions, such as pillows, are used tocontort the patient's body to temporarily (and at times, precariously)align his or her eye with the laser beam. In severe cases, evenmakeshift solutions are inadequate, meaning that these patients areunable to receive treatment because they cannot be physically alignedwith the vertical laser beam 800, as shown in FIG. 8.

Even for the majority of patients with normal spinal curvatures, subtlemisalignment may exist as the eye may not be precisely perpendicular tothe laser beam. The eye comprises complex optical structures, andmisaligning the eye with the surgical treatment apparatus can result inless than ideal placement of incisions in at least some instances.

For all these reasons, it would be desirable to provide improved methodsand systems that overcome at least some of the above limitations of theabove prior systems and methods.

SUMMARY

Hence, to obviate one or more problems due to limitations ordisadvantages of the related art, this disclosure provides embodimentsfor improved alignment of a laser beam pulse with an eye during surgery,improved placement of laser beam pulses to incise the eye, improvedplacement of refractive incisions on the eye, and improved placement ofincisions for intraocular lenses. Ideally, these improvements will toprovide an improved result for the patient, and provide treatmentoptions to a larger patient population.

Embodiments described in this disclosure provide improved treatment ofmaterials, such as tissue. In many embodiments, the tissue comprisesocular tissue, such as one or more of corneal and lenticular tissue,that are incised for refractive surgery, or one or more of cornealtissues incised during cataract procedures for the placement ofintraocular lenses, as well as for treatment of astigmatism. In manyembodiments, improved methods and apparatus for performing laser eyesurgery are provided for beneficially aligning laser incisions on tissuestructures of the eye. Many of the embodiments as disclosed herein arealso well suited for combination with laser eye surgery systems that donot rely on patient interfaces, such as laser surgical systems used incombination with pharmacological substances that may affect vision.

The optical structure of the eye may comprise one or more structures ofthe eye related to optics of the eye, and the tissue structure of theeye may comprise one or more tissues of the eye. The optical structureof the eye may comprise one or more of an optical axis of the eye, avisual axis of the eye, a line of sight of the eye, a pupillary axis ofthe eye, a fixation axis of the eye, a vertex of the cornea, an anteriornodal point of the eye, a posterior nodal point of the eye, an anteriorprincipal point of the eye, a posterior principal point of the eye, akeratometry axis, a center of curvature of the anterior corneal surface,a center of curvature of the posterior corneal surface, a center ofcurvature of the anterior lens capsule, a center of curvature of theposterior lens capsule, a center of the pupil, a center of the iris, acenter of the entrance pupil, or a center of the exit pupil of the eye.The optical structure of the eye may comprise a pre-contact opticalstructure determined with measurements obtained prior to the patientinterface contacting the eye, or a post-contact optical structure of theeye determined with measurements obtained when the patient interface hascontacted the eye.

In a first aspect, a laser surgery system is provided. In manyembodiments, a laser surgery system includes a laser source to produce aplurality of laser beam pulses. An optical delivery system is coupled tothe laser source to output the laser beam pulses at a predeterminedadjustable incident angle. The optical delivery system may include afirst rotator assembly receiving the beam from the laser source along afirst beam axis. The first rotator assembly may rotate around the firstbeam axis and the first rotator assembly may output the beam along asecond beam axis different from the first beam axis. The opticaldelivery system may include a second rotator assembly receiving the beamfrom the first rotator assembly along the second beam axis. The secondrotator assembly may rotate around the second beam axis. The secondrotator assembly may follow the rotation of the first rotator assembly.Rotation of the first rotator assembly may be independent of therotation of the second rotator assembly.

In many embodiments, the rotation of the first rotator assembly adjustsone of a polar angle and an azimuthal angle of the beam and rotation ofthe second rotator assembly adjusts the other of the polar angle and theazimuthal angle of the beam. The first rotator assembly and the secondrotator assembly may be beam expanders. In some embodiments, the firstrotator assembly and the second rotator assembly may redirect the beamperpendicularly by a respective first mirror and second mirror. Thesecond rotator assembly may output the beam along a third beam axis thatis different from the second beam axis.

In some embodiments, a patient interface is coupled to an output of theoptical delivery system for docking an eye to the patient interface. Thepatient interface rotates with the rotation of the first rotatorassembly and the second rotator assembly. The first rotator assembly andthe second rotator assembly may be axially symmetric. The laser sourcemay be an ultra-short pulsed laser source, such as a picosecond or afemtosecond laser source.

In another aspect, a method of adjusting an angle of incidence of alaser surgery system is provided. In some embodiments, the steps includegenerating a plurality of laser beam pulses by a laser source. The laserbeam pulses are output to an optical delivery system coupled to thelaser source. A first rotator assembly may receive the beam from thelaser source along a first beam axis. The first rotator assembly mayrotate around the first beam axis. The first rotator assembly may outputthe beam along a second beam axis different from the first beam axis.The second rotator assembly may receive the beam from the first rotatorassembly along the second beam axis. The second rotator assembly mayrotate around the second beam axis. The second rotator assembly mayfollow the rotation of the first rotator assembly. The rotation of thefirst rotator assembly is independent of the rotation of the secondrotator assembly. The laser beam pulses may be output by the opticaldelivery system to an eye at a predetermined adjustable incident angle.

In many embodiments, the rotation of the first rotator assembly adjustsone of a polar angle and an azimuthal angle of the beam and rotation ofthe second rotator assembly adjusts the other of the polar angle and theazimuthal angle of the beam. The first rotator assembly and the secondrotator assembly may be beam expanders. In some embodiments, the firstrotator assembly and the second rotator assembly redirect the beamperpendicularly by respective first mirror and second mirror. The secondrotator assembly may output the beam along a third beam axis differentfrom the second beam axis.

In some embodiments, a patient interface is coupled to an output of theoptical delivery system for docking an eye to the patient interface. Thepatient interface rotates with the rotation of the first rotatorassembly and the second rotator assembly. The first rotator assembly andthe second rotator assembly may be axially symmetric. The laser sourcemay be an ultra-short pulsed laser source such as a femtosecond lasersource.

In other embodiments, the method further includes the steps of measuringa cornea of an eye, determining an axis of the cornea, determining arotation of the first rotator assembly and the second rotator assemblyto align the incident angle of the output beam with the axis of thecornea, and rotating the first rotator assembly and the second rotatorassembly by the determined rotation.

In another aspect, a laser surgery system is provided. In someembodiments, a laser surgery system includes a laser source to produce aplurality of laser beam pulses. A measurement system measures a corneaof an eye. An optical delivery system is coupled to the laser source andthe measurement system to output the laser beam pulses at apredetermined adjustable incident angle. The optical delivery system mayinclude a first rotator assembly receiving the beam from the lasersource along a first beam axis. The first rotator assembly may rotatearound the first beam axis. The first rotator assembly may output thebeam along a second beam axis different from the first beam axis. Asecond rotator assembly may receive the beam from the first rotatorassembly along the second beam axis. The second rotator assembly mayrotate around the second beam axis. The second rotator assembly mayfollow the rotation of the first rotator assembly. The rotation of thefirst rotator assembly is independent of the rotation of the secondrotator assembly.

The system may further include a processor coupled to the laser source,measurement system and optical delivery system, the processor comprisinga tangible non-volatile computer readable medium comprising instructionsto determine an axis of the cornea by the measurement system, determinea rotation of the first rotator assembly and the second rotator assemblyto align the incident angle of the output beam with the axis of thecornea, and rotate the first rotator assembly and the second rotatorassembly by the determined rotation.

This summary and the following detailed description are merelyexemplary, illustrative, and explanatory, and are not intended to limit,but to provide further explanation of the invention as claimed.Additional features and advantages of the invention will be set forth inthe descriptions that follow, and in part will be apparent from thedescription, or may be learned by practice of the invention. Theobjectives and other advantages of the invention will be realized andattained by the structure particularly pointed out in the writtendescription, claims and the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 shows a perspective view illustrating an adjustable angle ofincidence of a laser beam according to many embodiments;

FIG. 2 shows a flowchart of an alignment method of a laser beam with aneye according to many embodiments;

FIG. 3 shows a perspective view showing a laser eye surgery systemaccording to many embodiments;

FIG. 4 shows a simplified block diagram showing a top level view of theconfiguration of a laser eye surgery system according to manyembodiments;

FIG. 5 shows a simplified block diagram illustrating the configurationof a laser eye surgery system according to many embodiments;

FIG. 6A shows a plan view diagram illustrating the configuration of abeam delivery system of a laser eye surgery system according to manyembodiments;

FIG. 6B shows a side view diagram illustrating the configuration of abeam delivery system of a laser eye surgery system according to manyembodiments;

FIG. 6C shows a side view diagram illustrating the configuration of abeam delivery system of a laser eye surgery system according to manyembodiments;

FIG. 6D shows another side view diagram illustrating the configurationof a beam delivery system of a laser eye surgery system according tomany embodiments;

FIG. 6E shows another side view diagram illustrating the configurationof a beam delivery system of a laser eye surgery system according tomany embodiments;

FIG. 7 shows a cross-sectional view of a rotatable beam expander in abeam path of a laser eye surgery system according to many embodiments;

FIG. 8 shows a perspective view illustrating a fixed angle of incidenceof a laser beam according to the prior art.

DETAILED DESCRIPTION

The following description describes various embodiments of the presentinvention. For purposes of explanation, specific configurations anddetails are set forth so as to provide a thorough understanding of theembodiments. It will also, however, be apparent to one of ordinary skillin the art that embodiments of the present invention can be practicedwithout certain specific details. Further, to avoid obscuring theembodiment being described, various well-known features may be omittedor simplified in the description.

Methods and systems related to laser eye surgery are disclosed. In manyembodiments, a laser is used to form precise incisions in the cornea, inthe lens capsule, and/or in the crystalline lens nucleus. Althoughspecific reference is made to tissue cutting for laser eye surgery,embodiments as described herein can be used in one or more of many wayswith many surgical procedures and devices, such as microkeratomes anddevices used for orthopedic surgery and robotic surgery.

The embodiments as described herein are particularly well suited fortreating tissue, such as with the surgical treatment of tissue. In manyembodiments, the tissue comprises an optically transmissive tissue, suchas tissue of an eye. The embodiments as described herein can be combinedin many ways with one or more of many known refractive surgicalprocedures such as cataract surgery, corneal incisions, LASIK, all laserLASIK, femto LASIK, corneaplasty, astigmatic keratotomy, cornealrelaxing incision (hereinafter “CRI”), Limbal Relaxing Incision(hereinafter “LRI”), photorefractive keratectomy (hereinafter “PRK”) andSmall Incision Lens Extraction (hereinafter “SMILE”), for example. Theembodiments as described herein can be particularly well suited forincreasing the accuracy of the cutting of the material such as tissue,for example.

The embodiments as described herein are particularly well suited forcombination with cataract surgery used for placement of intraocularlenses, as well as for with components of one or more known intraocularlenses such as one or more of accommodating intraocular lenses orintraocular lenses to correct aberrations of the eye. The embodimentsdisclosed herein can be also used to combine refractive surgicalprocedures with cataract surgery for placement of intraocular lenses,for example.

The embodiments as described herein can be used to position incisions ofthe lens capsule sized to receive structures of an intraocular lens inorder to retain the placed IOL in alignment with one or more axes theeye as described herein.

The embodiments disclosed herein are well suited for combination withprior laser surgery systems, such as the iFS Advanced Femtosecond Laser,the IntraLase FS Laser, the Catalys Precision Laser System, and similarsystems. Such systems can be modified according to the teachingsdisclosed herein, and to more accurately measure and treat the eye.

As used herein, like characters such as reference numerals and lettersdescribe like elements. As used herein, the terms anterior and posteriorrefers to known orientations with respect to the patient. Depending onthe orientation of the patient for surgery, the terms anterior andposterior may be similar to the terms upper and lower, respectively,such as when the patient is placed in a supine position on a bed. Theterms distal and anterior may refer to an orientation of a structurefrom the perspective of the user, such that the terms proximal anddistal may be similar to the terms anterior and posterior when referringto a structure placed on the eye, for example. A person of ordinaryskill in the art will recognize many variations of the orientation ofthe methods and apparatus as described herein, and the terms anterior,posterior, proximal, distal, upper, and lower are used merely by way ofexample.

As used herein, the terms first and second are used to describestructures and methods without limitation as to the order of thestructures and methods which can be in any order, as will be apparent toa person of ordinary skill in the art based on the teachings providedherein.

The embodiments disclosed herein enable accurate and precise alignmentof an eye with an angle of incidence of a beam for subsequentintegration with the laser treatment.

FIG. 1 shows a perspective view illustrating an adjustable angle ofincidence of a laser beam, according to many embodiments. An incidentangle of beam 100 may be adjusted in a polar angle θ and azimuthal angleφ so as to generate an adjustable beam within a predetermined cone. Byintroducing two mutually perpendicular rotations about the beam axis inthe common propagation path, adjustment of the incident angle isprovided within a predetermined range. By providing an adjustableincident angle of the output beam, alignment between the system and eyeis improved, leading to improved patient comfort and surgical outcomes.Systems providing an adjustable incident angle, as described in detailbelow, do not significantly add to the size and weight of a lasersurgery system

FIG. 2 shows a flow chart of a method 200 for providing alignment of acornea with an output laser beam, according to embodiments. The method200 comprises the following main steps. In a step 210, the patient's eyeis positioned within the capture/output range of a beam delivery andvisualization system 20 of a laser eye surgery system described herein.In a step 220, the visualization system is used to measure the eye anddetermine a corresponding incident angle of the output beam.Alternatively, an operator such as a surgeon may also visually determinethe angle of incidence of the output beam and may input the parametersinto a control panel/GUI 50. In a step 230, a rotation mechanism isrotated to output a laser beam that is aligned with the cornea axisdetermined in step 220.

Positioning step 210: In the step 210, the patient's eye is positionedwithin the capture range of a beam delivery and visualization system 20of the laser eye surgery system 2 as described herein, such as shown inFIGS. 3-5, for example. Positioning of the patient for laser surgery istypically enabled by motion of a patient bed or by motion of the lasersystem 2. Typically, the operator has manual control of the lateral andaxial position, guiding a docking mechanism or patient interface 40 intoplace. In the absence of a docking mechanism, the operator can beprovided with means for guiding the motion so that the eye, such thatthe cornea is placed within the operative range of the measurementand/or beam delivery system 20. This can be accomplished with thesubsystems of iFS and similar systems, with some modifications accordingto embodiments disclosed herein. Initial patient position can be guidedby a video camera 29, guiding the eye into lateral position by centeringthe video image, and into axial position by focusing the image. At thispoint, the cornea is placed within the capture range of a measurementsystem, typically X mm to Y mm axially. For example, an OCT system canbe used to measure the axial position of the cornea, and a suitabledisplay 50 provides the operator guidance for final, accuratepositioning. Alternatively, a visual imaging system such as a camera, acamera coupled to a microscope which may share optics with the lasersystem 2, a CCD, among others may be used instead of the OCT system tofacilitate the positioning step 210.

For the laser eye surgery system 2, an optical coherence tomography(OCT) system of a beam delivery and visualization system 20 may be usedto position the patient eye in the step 210 and/or to measure the shapeof the cornea in the step 220. The system 2 may apply any number ofmodalities to measure the shape of the eye including one or more of akeratometry reading of the eye, a corneal topography of the eye, anoptical coherence tomography of the eye, a Placido disc topography ofthe eye, a reflection of a plurality of points from the corneatopography of the eye, a grid reflected from the cornea of the eyetopography, a Hartmann-Shack topography of the eye, a Scheimpflug imagetopography of the eye, a confocal tomography of the eye, or a lowcoherence reflectometry of the eye. The shape of the cornea can bemeasured before, during, or after the patient interface 40 is dockedwith the eye of the patient. Images captured by the beam delivery andvisualization system 20 of the laser eye surgery system 2 may bedisplayed with a display of the control panel/GUI 50 of the laser eyesurgery system 2. The control panel/GUI 50 may also be used to modify,distort, or transform any of the displayed images.

Determination step 220: In the step 220, a controller/processor 30 ofthe laser eye surgery system can be used to determine a degree ofrotation of rotation mechanisms(s) to align with the optical axis. Anoperator may also visually determine the alignment angle. The opticalaxis of the cornea may be represented as a polar angle and azimuthalangle in a spherical coordinate system where the Z axis is the verticalaxis and the XY plane is parallel to ground (FIG. 1). The beam deliveryand visualization system 20 can be used to measure one or more opticalstructures of the eye. The beam delivery and visualization system 20includes sensors to image one or more tissue structures of the eye andcan be used to determine one or more axes of the eye as describedherein. The beam delivery and visualization system 20 can image andprofile one or more structures of the eye as described herein, such asone or more of the cornea of the eye, the anterior surface of thecornea, the posterior surface of the cornea, the iris of the eye, thepupil of the eye, the natural pupil of the eye, the lens of the eye, theanterior capsule of the lens, the posterior capsule of the lens, theentrance pupil of the eye, the natural entrance pupil of the eye, thevertex of the cornea. In many embodiments, tomography of the cornea iscombined with surface topography of the cornea and the video cameraimages of the cornea to determine one or more axes of the eye. Thevertex of the cornea may comprise a central part of the cornea locatedalong the optical axis of the eye that extends substantiallyperpendicular to the plane of the eye, and may comprise a center of thecornea as determined in response to a measurement of the limbusextending around the perimeter of the cornea.

In many embodiments, a visualization subsystem is used to determine oneor more of the optical axis of the eye, the center of curvature of theanterior corneal surface, the center of curvature of the posteriorcorneal surface, the center of curvature of the lens capsule anteriorsurface, or the center of curvature of lens capsule posterior surface.The optical axis of the eye may comprise a straight line extending fromthe center of curvature of the anterior surface of the cornea to thecenter of curvature of the posterior surface of the posterior lenscapsule.

When the corneal surfaces have been mapped, polynomial fittingalgorithms or other fitting algorithms can be used to calculate usefulparameters of the cornea such as one or more of the axis of the cornea,optical power of the cornea, the astigmatic axis angle, and astigmatismmagnitude, for example.

Examples of fitting algorithms suitable for mapping optical tissuesurfaces include elliptical surfaces, Fourier transforms, polynomials, aspherical harmonics, Taylor polynomials, a wavelet transform, or Zernikepolynomials. In many embodiments, three dimensional elevation profiledata of an optical tissue surface of the eye is provided, and the datafit to the optical tissue surface. The optical tissue surface maycomprise one or more of the anterior surface of the cornea, theposterior surface of the cornea, the anterior surface of the lenscapsule, the posterior surface of the lens capsule, an anterior surfaceof the lens cortex, a posterior surface of the lens cortex, an anteriorsurface of the lens nucleus, a posterior surface of the lens nucleus,one or more anterior surfaces of the lens having a substantiallyconstant index of refraction, one or more posterior surfaces of the lenshaving a substantially constant index of refraction, the retinalsurface, the foveal surface, a target tissue surface to correct visionsuch as a target corneal surface, an anterior surface of an intraocularlens, or a posterior surface of an intraocular lens, for example. As theindex of refraction of the lens can vary from about 1.36 to about 1.41,optical surfaces of the lens may define one or more layers of the lenshaving a similar index of refraction, for example.

Rotation step 230: In the step 230, the incident angle of the outputbeam is rotated according to the determined rotation of step 220. Therotation mechanism may include a first and second rotator assembly. Arotation of a first rotator assembly and a second rotator assembly maythen be determined by the processor to align the incident angle of theoutput beam with the axis of the cornea.

For example, the processor 30 may instruct the first rotator assembly torotate by a polar angle θ and the second rotator assembly to rotate byan azimuthal angle φ to rotate the incident angle of the output beam toalign with the optical axis. The first rotator assembly and the secondrotator assembly are rotated accordingly by two mutually perpendicularrotations each around the axis of the laser beam. Accordingly, thesecond rotator assembly follows the rotation of the first rotatorassembly and rotation of the first rotator assembly is independent ofthe rotation of the second rotator assembly. By introducing a rotationinside a beam delivery system 20 instead of rotating the system 2 as awhole, the weight of the rotation mechanism is reduced. The processorsystem may comprise a tangible medium embodying computer programinstructions to perform one or more of the method steps as describedherein.

FIG. 3 shows a laser eye surgery system 2 according to many embodiments,operable to form precise incisions in the cornea, in the lens capsule,and/or in the crystalline lens nucleus. The system 2 includes a mainunit 3 including many primary subsystems of the system 2. For example,externally visible subsystems include a display control panel 50 and apatient interface assembly 4 including patient interface 40. The patientinterface assembly 4 is configured to be adjusted and oriented in threeaxes (X-axis, Y-axis, and Z-axis).

In many embodiments, the system 2 includes external communicationconnections. For example, the system 2 can include a network connection(e.g., an RJ45 network connection) for connecting the system 2 to anetwork. The network connection can be used to enable network printingof treatment reports, remote access to view system performance logs, andremote access to perform system diagnostics. The system 2 can include avideo output port (e.g., HDMI) that can be used to output video oftreatments performed by the system 2. The output video can be displayedon an external monitor for, for example, viewing by family membersand/or training. The output video can also be recorded for, for example,archival purposes. The system 2 can include one or more data outputports (e.g., USB) to, for example, enable export of treatment reports toa data storage device. The treatments reports stored on the data storagedevice can then be accessed at a later time for any suitable purposesuch as, for example, printing from an external computer in the casewhere the user without access to network based printing.

FIG. 4 shows a simplified block diagram of the system 2. The system 2includes a laser engine 10, a beam delivery and visualization system 20,control electronics 30, patient interface 40, and control panel/GUI 50.The control electronics 30 is operatively coupled via communicationpaths with the laser engine 10, beam delivery and visualization system20, patient interface 40 and control panel/GUI 50.

The beam delivery and visualization system 20 focuses light to generatea tissue effect, such as photodisruption to treat an eye 43. The beamdelivery and visualization system 20 also scans the eye 43 for treatmentplanning to form a cutting pattern in the eye. In addition, the beamdelivery and visualization system 20 provides an output beam with twodegrees of freedom to rotate along an azimuthal angle and polar angle ina spherical coordinate system (see FIG. 1).

FIG. 5 shows a simplified block diagram illustrating the configurationof a laser eye surgery system, according to many embodiments. In manyembodiments, laser engine 10 incorporates ultra-short pulsed laser,including for example, femtosecond (FS) laser technology. By usingfemtosecond laser technology, a short duration (e.g., approximately10⁻¹³ seconds in duration) laser pulse (with energy level in the microjoule range) can be delivered to a tightly focused point to disrupttissue, thereby substantially lowering the energy level required ascompared to the level required for ultrasound fragmentation of the lensnucleus and as compared to laser pulses having longer durations.

The laser engine 10 can produce laser pulses having a wavelengthsuitable to the configuration of the system 2. As a non-limitingexample, the system 2 can be configured to use a laser engine 10 thatproduces laser pulses having a wavelength from 1020 nm to 1050 nm. Forexample, the laser engine 10 can have a diode-pumped solid-stateconfiguration with a 1030 (+/−5) nm center wavelength.

The laser engine 10 can include control and conditioning components. Forexample, such control components can include components such as a beamattenuator 12 to control the energy of the laser pulse produced by alaser source 11 and the average power of the pulse train, a fixedaperture to control the cross-sectional spatial extent of the beamcontaining the laser pulses, an energy control unit 13 including one ormore power monitors to monitor the flux and repetition rate of the beamtrain and therefore the energy of the laser pulses, and a shutter 14 toallow/block transmission of the laser pulses. Such conditioningcomponents can include an adjustable zoom assembly to adapt the beamcontaining the laser pulses to the characteristics of the system 2 and afixed optical relay 15 to transfer the laser pulses over a distancewhile accommodating laser pulse beam positional and/or directionalvariability, thereby providing increased tolerance for componentvariation.

The beam delivery and visualization system 20 is configured to measurethe spatial disposition of eye structures in three dimensions. Themeasured eye structures can include the anterior and posterior surfacesof the cornea, the anterior and posterior portions of the lens capsule,the iris, and the limbus. In many embodiments, the system 20 utilizesoptical coherence tomography (OCT) imaging. As a non-limiting example,the system 2 can be configured to use an OCT imaging system employingwavelengths from 780 nm to 970 nm. For example, system 20 can include anOCT imaging system that employs a broad spectrum of wavelengths from 810nm to 850 nm. Such an OCT imaging system can employ a reference pathlength that is adjustable to adjust the effective depth in the eye ofthe OCT measurement, thereby allowing the measurement of systemcomponents including features of the patient interface that lie anteriorto the cornea of the eye and structures of the eye that range in depthfrom the anterior surface of the cornea to the posterior portion of thelens capsule and beyond.

The beam delivery and visualization system 20 can include a laser or LEDlight source and a detector to monitor the alignment and stability ofthe actuators used to position the beam in X, Y, and Z, as well as thepolar angle and azimuthal angle of the beam. The system 20 can include avideo system that can be used to provide imaging of the patient's eye tofacilitate docking of the patient's eye 43 to the patient interface 40.The imaging system provided by the video system can also be used todirect via the GUI 50 the location of cuts. The imaging provided by thevideo system can additionally be used during the laser eye surgeryprocedure to monitor the progress of the procedure, to track movementsof the patient's eye 43 during the procedure, and to measure thelocation and size of structures of the eye such as the pupil and/orlimbus.

The generated laser pulse beam 16 proceeds from laser engine 10 throughan articulated arm 21. The laser pulse beam 16 may vary from unit tounit, particularly when the laser source 11 may be obtained fromdifferent laser manufacturers. For example, the beam diameter of thelaser pulse beam 16 may vary from unit to unit (e.g., by +/−20%). Thebeam may also vary with regard to beam quality, beam divergence, beamspatial circularity, and astigmatism.

After exiting the articulated arm 21, the laser pulse beam 16 proceedsthrough a beam steering shutter 22. A portion of the beam is reflectedto a beam monitor 23. The laser pulse beam 16 proceeds through apre-beam expander 24 and then a 6 x beam expander 26. An IR mirror 27reflects the emission towards an objective lens 28. The beam is thenoutput through a patient interface 40 to a patient eye 43. A videocamera 29 may be provided between the beam expander 26 and objectivelens 28.

The beam delivery and visualization system 20 provides a commonpropagation path that is disposed between the patient interface 40 andthe laser engine 10. In many embodiments, the beam delivery andvisualization system 20 includes beam expanders 24, 26 to propagate theemission along the common propagation path to the patient interface 40.In many embodiments, the beam delivery and visualization system 20includes an objective lens assembly 28 that focuses each laser pulseinto a focal point. In many embodiments, the beam delivery andvisualization system 20 includes scanning mechanisms 17, 25 operable toscan the respective emission in three dimensions. For example, thesystem 2 can include an XY-scan mechanism(s) 25 and a Z-scan mechanism17. The XY-scan mechanism(s) 25 can be used to scan the respectiveemission in two dimensions transverse to the propagation direction ofthe respective emission. The Z-scan mechanism 17 can be used to vary thedepth of the focal point within the eye 43. By themselves, the XY-scanmechanism 25 and Z-scan mechanism 17 do not alter an incident angle ofthe output beam. In many embodiments, the scanning mechanisms aredisposed between the laser diode 11 and the objective lens 28 such thatthe scanning mechanisms are used to scan the alignment laser beamproduced by the laser diode. In contrast, in many embodiments, the videosystem is disposed between the scanning mechanisms and the objectivelens such that the scanning mechanisms do not affect the image obtainedby the video system.

After reflection by the IR mirror 27, the laser pulse beam 16 passesthrough an objective lens assembly 28. The objective lens assembly 28can include one or more lenses. In many embodiments, the objective lensassembly 28 includes multiple lenses. The complexity of the objectivelens assembly 28 may be driven by the scan field size, the focused spotsize, the degree of telecentricity, the available working distance onboth the proximal and distal sides of objective lens assembly 28, aswell as the amount of aberration control. After passing through theobjective lens assembly 28, the laser pulse beam 66 passes through thepatient interface 52.

The beam delivery and visualization system 20 may include a rotationmechanism that allow the pulsed beam output by the system 2 to adjust anincident angle for alignment with the eye, as illustrated in detail inFIG. 6.

The rotation mechanism allowing this angle adjustment are describedlater in detail, but may be configured along the beam path anywherebetween the laser 11 and patient interface 40. Preferably, the rotationcomponents are provided near the patient interface 40 so as to reducethe size and number of subsystems to be rotated. The rotation mechanismmay be controlled by the control electronics 30 or by manual adjustment,and can include suitable components, such as a motor, galvanometer, orany other well-known optic moving device. For a rotation mechanismadjacent to the patient interface 40, the rotation mechanism alsorotates the downstream patient interface 40. Likewise, if the rotationmechanism is incorporated just after the laser 11 in FIG. 5, then eachof the downstream laser engine 10, the beam delivery and visualizationsystem 20 and patient interface 40 are rotated, thus increasing the sizeand complexity of the rotation mechanism.

The patient interface 40 is used to restrain the position of thepatient's eye 43 relative to the system 2. In many embodiments, thepatient interface 40 employs a suction ring that is vacuum attached tothe patient's eye 43. The suction ring is then coupled with the patientinterface 40, for example, using vacuum to secure the suction ring tothe patient interface 40. In many embodiments, the patient interface 40includes an optically transmissive structure having a posterior surfacethat is displaced vertically from the anterior surface of the patient'scornea and a region of a suitable liquid (e.g., a sterile bufferedsaline solution (BSS) such as Alcon BSS (Alcon Part Number 351-55005-1)or equivalent) is disposed between and in contact with the patientinterface lens posterior surface and the patient's cornea and forms partof a transmission path between the beam delivery and visualizationsystem 20 and the patient's eye 43. In many embodiments, the patientinterface lens is disposable and can be replaced at any suitableinterval, such as before each eye treatment.

The control electronics 30 controls the operation of and can receiveinput from the laser engine 10, beam delivery and visualization system20, the patient interface 40, and the control panel/GUI 50 via thecommunication paths. The communication paths can be implemented in anysuitable configuration, including any suitable shared or dedicatedcommunication paths between the control electronics 30 and therespective system components. The control electronics 30 can include anysuitable components, such as one or more processor, one or morefield-programmable gate array (FPGA), and one or more memory storagedevices. In many embodiments, the control electronics 30 controls thecontrol panel/GUI 50 to provide for pre-procedure planning according touser specified treatment parameters as well as to provide user controlover the laser eye surgery procedure.

The GUI 50 can include any suitable user input device suitable toprovide user input to the control electronics 30. For example, the userinterface devices can include devices such as, for example, a controlkeypad and a patient interface radio frequency identification (RFID)reader. The configuration of FIG. 5 is a non-limiting example ofsuitable configurations and integration of the laser engine 10, the beamdelivery and visualization system 20, and the patient interface 40.Other configurations and integration of subsystems may be possible andmay be apparent to a person of skill in the art.

The system 2 is operable to project and scan optical beams into thepatient's eye 43. The laser engine 10 includes an ultrafast (UF) laser11 (e.g., a femtosecond or a picosecond laser). Optical beams can bescanned in the patient's eye 43 in three dimensions: X, Y, Z. Forexample, short-pulsed laser light generated by the laser 11 can befocused into eye tissue to produce dielectric breakdown to causephotodisruption around the focal point (the focal zone), therebyrupturing the tissue in the vicinity of the photo-induced plasma. In thesystem 2, the wavelength of the laser light can vary between 800 nm to1200 nm and the pulse width of the laser light can vary from 10 fs to10000 fs. The pulse repetition frequency can also vary from 10 kHz to500 kHz. Safety limits with regard to unintended damage to non-targetedtissue bound the upper limit with regard to repetition rate and pulseenergy. Threshold energy, time to complete the procedure, and stabilitycan bound the lower limit for pulse energy and repetition rate. The peakpower of the focused spot in the eye 43, and specifically within thecrystalline lens and the lens capsule of the eye, is sufficient toproduce optical breakdown and initiate a plasma-mediated ablationprocess. Near-infrared wavelengths for the laser light are preferredbecause linear optical absorption and scattering in biological tissue isreduced for near-infrared wavelengths. As an example, the laser 11 canbe a repetitively pulsed 1031 nm device that produces pulses with lessthan 600 fs duration at a repetition rate of 120 kHz (+/−5%) andindividual pulse energy in the 1 to 20 micro joule range.

The laser engine 10 is controlled by the control electronics 30 and theuser, via the control panel/GUI 50 to create a laser pulse beam 16. Thecontrol panel/GUI 50 is used to set system operating parameters, processuser input, display gathered information such as images of ocularstructures, and display representations of incisions to be formed in thepatient's eye 43.

The XY-scanner 25 is controlled by the control electronics 30, and caninclude suitable components, such as a motor, galvanometer, or any otherwell-known optic moving device. The XY-scanner 25 is configured to scanthe laser pulse beam 16 in two dimensions transverse to the Z axis andthe propagation direction of the laser pulse beam 16. The XY-scanner 25changes the resulting direction of the laser pulse beam 16, causinglateral displacements of the UF focus point located in the patient's eye43. Similarly, the Z-scanner 17 is controlled by the control electronics30, and can include suitable components, such as a motor, galvanometer,or any other well-known optic moving device. The Z-scanner 17 isconfigured transverse to the XY plane, causing vertical displacements ofthe UF focus point located in the patient's eye 43.

The beam delivery and visualization system 20 under the control of thecontrol electronics 54 can automatically generate aiming, ranging, andtreatment scan patterns. Such patterns can be comprised of a single spotof light, multiple spots of light, a continuous pattern of light,multiple continuous patterns of light, and/or any combination of these.In addition, the aiming pattern need not be identical to the treatmentpattern (using the laser pulse beam 16), but can optionally be used todesignate the boundaries of the treatment pattern to provideverification that the laser pulse beam 16 will be delivered only withinthe desired target area for patient safety. This can be done, forexample, by having the aiming pattern provide an outline of the intendedtreatment pattern. This way the spatial extent of the treatment patterncan be made known to the user, if not the exact locations of theindividual spots themselves, and the scanning thus optimized for speed,efficiency, and/or accuracy. The aiming pattern can also be made to beperceived as blinking in order to further enhance its visibility to theuser. Likewise, a ranging beam need not be identical to the treatmentbeam or pattern. The ranging beam needs only to be sufficient enough toidentify targeted surfaces. These surfaces can include the cornea andthe anterior and posterior surfaces of the lens and may be consideredspheres with a single radius of curvature. Also the optics shared by avideo subsystem does not have to be identical to those shared by thetreatment beam. The positioning and character of the laser pulse beam 16and/or the scan pattern the laser pulse beam 16 forms on the eye 43 maybe further controlled by use of an input device such as a joystick, orany other appropriate user input device (e.g., control panel/GUI 50) toposition the patient and/or the optical system.

The control electronics 30 can be configured to target the targetedstructures in the eye 43 and ensure that the laser pulse beam 16 will befocused where appropriate and not unintentionally damage non-targetedtissue. Imaging modalities and techniques described herein, such asthose mentioned above, or ultrasound may be used to determine thelocation and measure the thickness of the lens and lens capsule toprovide greater precision to the laser focusing methods, including 2Dand 3D patterning. Laser focusing may also be accomplished by using oneor more methods including direct observation of an aiming beam, or otherknown ophthalmic or medical imaging modalities, such as those mentionedabove, and/or combinations thereof. Additionally the ranging subsystemsuch as an OCT can be used to detect features or aspects involved withthe patient interface. Features can include fiducials places on thedocking structures and optical structures of the disposable lens such asthe location of the anterior and posterior surfaces.

Additionally or alternatively, imaging modalities other than OCT imagingcan be used. An OCT scan of the eye can be used to measure the spatialdisposition (e.g., three dimensional coordinates such as X, Y, and Z ofpoints on boundaries) of structures of interest in the patient's eye 43.Such structure of interest can include, for example, the anteriorsurface of the cornea, the posterior surface of the cornea, the anteriorportion of the lens capsule, the posterior portion of the lens capsule,the anterior surface of the crystalline lens, the posterior surface ofthe crystalline lens, the iris, the pupil, and/or the limbus. Thespatial disposition of the structures of interest and/or of suitablematching geometric modeling such as surfaces and curves can be generatedand/or used by the control electronics 30 to program and control thesubsequent laser-assisted surgical procedure. The spatial disposition ofthe structures of interest and/or of suitable matching geometricmodeling can also be used to determine a wide variety of parametersrelated to the procedure such as, for example, the upper and lower axiallimits of the focal planes used for cutting the lens capsule andsegmentation of the lens cortex and nucleus, and the thickness of thelens capsule among others.

The system 2 can be set to locate the anterior and posterior surfaces ofthe lens capsule and cornea and ensure that the UF laser pulse beam 16will be focused on the lens capsule and cornea at all points of thedesired opening. Imaging modalities and techniques described herein,such as for example, Optical Coherence Tomography (OCT), and such asPurkinje imaging, Scheimpflug imaging, confocal or nonlinear opticalmicroscopy, fluorescence imaging, ultrasound, structured light, stereoimaging, or other known ophthalmic or medical imaging modalities and/orcombinations thereof may be used to determine the shape, geometry,perimeter, boundaries, and/or 3-dimensional location of the lens andlens capsule and cornea to provide greater precision to the laserfocusing methods, including 2D and 3D patterning. Laser focusing mayalso be accomplished using one or more methods including directobservation of an aiming beam, or other known ophthalmic or medicalimaging modalities and combinations thereof, such as but not limited tothose defined above.

Optical imaging of the cornea, anterior chamber and lens can beperformed using the same laser and/or the same scanner used to producethe patterns for cutting. Optical imaging can be used to provideinformation about the axial location and shape (and even thickness) ofthe anterior and posterior lens capsule, the boundaries of the cataractnucleus, as well as the depth of the anterior chamber and features ofthe cornea. This information may then be loaded into the laser 3-Dscanning system or used to generate a three dimensionalmodel/representation/image of the cornea, anterior chamber, and lens ofthe eye, and used to define the cutting patterns used in the surgicalprocedure.

FIG. 6A shows a plan view diagram illustrating the configuration of abeam delivery subsystem 600 of a laser eye surgery system 2, accordingto many embodiments.

The subsystem 600 includes a fixed assembly 610 that does not rotate.The pulsed beam 605 may enter the fixed assembly 610 from a laser engine10. The beam 605 enters and exits the fixed assembly 610 along a firstbeam axis 620. The fixed assembly 610 may include a plurality of lenses(not shown), for example.

The beam 605 is then input to a first rotator assembly 612 that rotatesrelative to the fixed assembly 610 about the first beam axis 620. Thefirst rotator assembly 612 includes a first mirror 613 that preferablyreflects the beam 605 perpendicularly from a first beam path to a secondbeam path. The reflected beam 605 is directed along a second beam axis630. The beam 605 exits the first rotator assembly 612 along the secondbeam axis 630. When the first rotator assembly 612 rotates, the firstmirror 613 rotates accordingly so as to alter the angle at which thebeam 605 is reflected perpendicularly. Due to the rotation of the firstrotator assembly 612 about the first beam axis 620, the beam 605 isprovided a first degree of freedom for adjustment of the incident angle.

The beam 605 is then input to a second rotator assembly 614 that rotatesrelative to the first rotator assembly 612 about the second beam axis630. The second rotator assembly 614 includes a mirror 615 thatpreferably reflects the beam 605 perpendicularly from a second beam axisto a third beam axis. When the second rotator assembly 614 rotates, thesecond mirror 615 rotates accordingly so as to alter the angle at whichthe beam 605 is reflected perpendicularly. Due to the rotation of thesecond rotator assembly 614 about the second beam axis 630, the beam 605is provided a second degree of freedom for adjustment of the incidentangle. The twice-reflected beam 605 is then output to an objective lensassembly 616 (not shown in FIG. 6A). The first rotator assembly 612 andthe second rotator assembly 614 may be rotated manually or by controller30. As best shown in FIG. 6B, the second rotator assembly 614 mayinclude a mirror 617 (not shown in FIG. 6A) that reflects the beam 605toward a patient interface 40 (not shown in FIG. 6A) for output to aneye 43. The second rotator assembly 614 follows the rotation of thefirst rotator assembly 612. The rotation of the first rotator assembly612 is independent of the rotation of the second rotator assembly 614.

FIG. 6B shows a side view diagram illustrating the configuration of abeam delivery system of a laser eye surgery system, according to manyembodiments. FIG. 6B illustrates a configuration of the second rotatorassembly 614 and patient interface 40 in the YZ plane. FIG. 6B shows asecond mirror 615 of the second rotator assembly 614 that reflects thebeam 605 along the third beam axis. The second rotator assembly 614 mayinclude a third mirror 617 that redirects the beam 605 perpendicularlytowards the patient interface 40. The beam 605 is then output from thepatient interface 40 and onto the eye 43. FIG. 6B shows an unrotatedsubsystem 600 with a vertical incident angle of the beam 605. Althoughthe eye 43 is located directly underneath the beam 605, the eye 43 maybe tilted such that optical structures of the eye 43 are misaligned withrespect to the vertical beam 605. FIG. 6C illustrates a rotation of thesubsystem 600 in the YZ plane for aligning the beam 605 perpendicularlywith the optical structures of the eye 43.

FIG. 6C shows a side view diagram illustrating the configuration of abeam delivery system of a laser eye surgery system having the samecomponents of FIG. 6B. The second rotator assembly 614 is rotated aboutthe second rotation axis 630. Rotation of the second rotator assembly614 rotates the downstream patient interface 40 coupled to the secondrotator assembly 614. A second mirror 615 of the second rotator assembly614 reflects the beam 605 along the third beam axis different from thesecond beam axis 630. The second rotator assembly 614 may include amirror 617 that redirects the beam 605 perpendicularly towards thepatient interface 40. The beam 605 is then output from the patientinterface 40 and onto the eye 43. The incident angle of beam 605 isadjusted by an angle θ to match a tilt of the eye 43 by the rotation ofthe second rotator assembly 614.

FIG. 6D shows another side view diagram illustrating the configurationof a beam delivery system of a laser eye surgery system in the XZ planeincluding a first rotator assembly 612, second rotator assembly 614 andpatient interface 40. The first rotator assembly 612 receives the beam605 along the first beam axis 620 on a first beam path. The first mirror613 redirects the beam 605 along the second beam axis 630 on a secondbeam path towards the second rotator assembly 614. After the secondrotator assembly 614 redirects the beam on a third beam path, the mirror617 redirects the beam 605 perpendicularly downwards towards the patientinterface 40. The beam 605 is then output from the patient interface 40and onto the eye 43. FIG. 6D shows an unrotated subsystem 600 with avertical incident angle of the beam 605. Although the eye 43 is locateddirectly underneath the beam 605, the eye 43 may be tilted such thatoptical structures of the eye 43 are misaligned with respect to thevertical beam 605. FIG. 6E illustrates a rotation of the subsystem 600in the XZ plane for aligning the beam 605 perpendicularly with theoptical structures of the eye 43.

FIG. 6E shows another side view diagram illustrating the configurationof a beam delivery system of a laser eye surgery system, according tomany embodiments. The first rotator assembly 612 receives the beam 605along the first beam axis 620 on a first beam path. The first rotatorassembly 612 is rotated about the first rotation axis 620. Rotation ofthe first rotator assembly 612 rotates the downstream second rotatorassembly 614 and patient interface 52. First beam mirror 613 redirectsthe beam 605 along the second beam axis 630 on a second beam pathtowards the second rotator assembly 614. After the second rotatorassembly 614 redirects the beam on a third beam path, the mirror 617redirects the beam 605 perpendicularly downwards towards the patientinterface 40. The beam 605 is then output from the patient interface 40and onto the eye 43. The incident angle of beam 605 is adjusted by anangle φ to match a tilt of the eye 43 by the rotation of the firstrotator assembly 612.

Rotation of first rotator assembly 612 about first axis 620 and rotationof second rotator assembly 614 about second axis 630 provides twodegrees of freedom that allow the beam 605 to be adjusted in the polarangle θ and azimuthal angle φ. In this manner, subsystem 600 providesadjustment of an incident angle for patients who are unable to align theoptical structures of the eye 43 with a vertical incident angle of apulsed beam. The output pulse beam is output from the patient interface40 at any angle within a predetermined cone onto the XY plane.Consequently, the eye 43 need not be strictly perpendicular to theZ-axis.

FIG. 7 shows a rotatable beam expander 700 in a beam path of a laser eyesurgery system, according to many embodiments. Rotation between thefixed assembly 610 and the first rotator assembly 612, and between thefirst rotator assembly 612 and the second rotator assembly 614 may beprovided by the axially symmetric components illustrated in FIG. 7. Forexample, a beam expander 700 may include a first section 710 and asecond section 712 where the second section 712 is rotated relative tothe first section 710 about a beam axis 720. The beam expander 700 maybe a tube and may include a plurality of lenses 715, mirrors and othercomponents.

When the second section 712 of the beam expander 700 rotates, the beamitself does not change since the rotation of the expander 700 is aboutthe beam axis 720. However, after redirecting the beam axisperpendicularly by a mirror that rotates with the second section 712,rotation of the second section 712 generates one degree of freedom.Adding a second rotation to the system with another perpendicularredirection of the beam generates a second degree of freedom. Ifrotation is provided in combination with perpendicular beam redirection,then the polar angle θ is independent of azimuthal angle φ.

However, perpendicularity of the beam redirection is not a requirementso long as the two rotations are non-parallel. For example, mirrors 613and 615 may redirect the beam 605 at an angle between zero and ninetydegrees. In this case, the adjustment of polar angle θ will depend onthe degree of rotation of first rotator assembly 612 and second rotatorassembly 614, and likewise with azimuthal angle φ. In other words, twonon-parallel rotations of the beam also enable adjustment of θ and φ.

In some embodiments, the second section 712 may be L-shaped and includea mirror for redirecting the beam perpendicularly towards another beamexpander. The beam delivery subsystem 600 is not limited to rotation ofa cutting laser beam for photodisruption. Any of an observation beam,measurement beam and treatment beam generated may be input to a beamexpander 700 for adjustment of an incident angle in the same manner asdescribed above.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. The term “connected” is to beconstrued as partly or wholly contained within, attached to, or joinedtogether, even if there is something intervening. Recitation of rangesof values herein are merely intended to serve as a shorthand method ofreferring individually to each separate value falling within the range,unless otherwise indicated herein, and each separate value isincorporated into the specification as if it were individually recitedherein. All methods described herein can be performed in any suitableorder unless otherwise indicated herein or otherwise clearlycontradicted by context. The use of any and all examples, or exemplarylanguage (e.g., “such as”) provided herein, is intended merely to betterilluminate embodiments of the invention and does not pose a limitationon the scope of the invention unless otherwise claimed. No language inthe specification should be construed as indicating any non-claimedelement as essential to the practice of the invention. As used herein,the terms first and second are used to describe structures and methodswithout limitation as to the order of the structures and methods whichcan be in any order, as will be apparent to a person of ordinary skillin the art based on the teachings provided herein.

While certain illustrated embodiments of this disclosure have been shownand described in an exemplary form with a certain degree ofparticularity, those skilled in the art will understand that theembodiments are provided by way of example only, and that variousvariations can be made without departing from the spirit or scope of theinvention. Thus, it is intended that this disclosure cover allmodifications, alternative constructions, changes, substitutions,variations, as well as the combinations and arrangements of parts,structures, and steps that come within the spirit and scope of theinvention as generally expressed by the following claims and theirequivalents.

What is claimed is:
 1. A method of adjusting an angle of incidence of alaser surgery system, the method comprising: measuring a cornea of aneye; determining an angular orientation of an optical axis of thecornea; determining a first rotation angle of a first rotator assemblycontaining a first mirror and a second rotation angle by a secondrotator assembly containing a second mirror that align the incidentangle of an output beam with the angular orientation of the optical axisof the cornea; generating a laser beam containing a plurality of laserbeam pulses by a laser source; outputting the laser beam to an opticaldelivery system coupled to the laser source; receiving the beam from thelaser source by the first rotator assembly along a first beam axis;rotating the first rotator assembly containing the first mirror aroundthe first beam axis by the determined first rotation angle, whereinrotating the first rotator assembly causes the second rotator assemblycontaining the second mirror to follow the rotation of the first rotatorassembly; outputting the beam by the first rotator assembly along asecond beam axis different from the first beam axis by reflecting thebeam with the first mirror of the first rotator assembly; receiving thebeam by the second rotator assembly from the first rotator assemblyalong the second beam axis; rotating the second rotator assemblycontaining the second mirror around the second beam axis by thedetermined second rotation angle, wherein the rotation of the firstrotator assembly is independent of the rotation of the second rotatorassembly; outputting the beam by the second rotator assembly along athird beam axis different from the second beam axis by reflecting thebeam with the second mirror of the second rotator assembly; andoutputting the laser beam by the optical delivery system to the eye atthe incident angle.
 2. The method of claim 1, wherein rotation of thefirst rotator assembly adjusts one of a polar angle and an azimuthalangle of the beam and rotation of the second rotator assembly adjuststhe other of the polar angle and the azimuthal angle of the beam.
 3. Themethod of claim 1, wherein each of the first rotator assembly and thesecond rotator assembly includes a section of a beam expander.
 4. Themethod of claim 1, wherein the first rotator assembly and the secondrotator assembly redirect the beam perpendicularly by the respectivefirst mirror and second mirror.
 5. The method of claim 1, furthercomprising: coupling a patient interface to an output of the opticaldelivery system for docking the eye to the patient interface.
 6. Themethod of claim 5, wherein the patient interface rotates with therotation of the first rotator assembly and the second rotator assembly.7. The method of claim 1, wherein each of the first rotator assembly andthe second rotator assembly includes a component that is axiallysymmetric.
 8. The method of claim 1, wherein the laser source is afemtosecond laser source.
 9. A laser surgery system, comprising: a lasersource to produce a laser beam containing a plurality of laser beampulses; a measurement system for measuring a cornea of an eye; anoptical delivery system coupled to the laser source and the measurementsystem to output the laser beam at a predetermined adjustable incidentangle, the optical delivery system comprising: a first rotator assemblycontaining a first mirror and receiving the beam from the laser sourcealong a first beam axis, wherein the first rotator assembly rotatesaround the first beam axis and the first mirror of the first rotatorassembly reflects the beam along a second beam axis different from thefirst beam axis; a second rotator assembly containing a second mirrorand receiving the beam from the first rotator assembly along the secondbeam axis, wherein the second rotator assembly rotates around the secondbeam axis and the second mirror of the second assembly reflects the beamalong a third beam axis different from the second beam axis, wherein thesecond rotator assembly follows the rotation of the first rotatorassembly and the rotation of the first rotator assembly is independentof the rotation of the second rotator assembly; a processor coupled tothe laser source, measurement system and optical delivery system, theprocessor comprising a tangible non-volatile computer readable mediumcomprising instructions to: determine an angular orientation of anoptical axis of the cornea by the measurement system; determine arotation of the first rotator assembly and the second rotator assemblyto align the incident angle of the output beam with the angularorientation of the optical axis of the cornea; and rotate the firstrotator assembly and the second rotator assembly by the determinedrotation.
 10. The laser surgery system of claim 9, wherein rotation ofthe first rotator assembly adjusts one of a polar angle and an azimuthalangle of the beam and rotation of the second rotator assembly adjuststhe other of the polar angle and the azimuthal angle of the beam. 11.The laser surgery system of claim 9, wherein each of the first rotatorassembly and the second rotator assembly includes a section of a beamexpander.
 12. The laser surgery system of claim 9, wherein the firstrotator assembly and the second rotator assembly redirect the beamperpendicularly by the respective first mirror and second mirror. 13.The laser surgery system of claim 9, further comprising: a patientinterface coupled to an output of the optical delivery system fordocking an eye to the patient interface.
 14. The laser surgery system ofclaim 13, wherein the patient interface rotates with the rotation of thefirst rotator assembly and the second rotator assembly.
 15. The lasersurgery system of claim 9, wherein each of the first rotator assemblyand the second rotator assembly includes a component that is axiallysymmetric.
 16. The laser surgery system of claim 9, wherein the lasersource is a femtosecond laser source.